Yokozuna Brake Cable Rust!

So I built up my Cervelo S3 in late Feb 2011. I chose Yokozuna cables; PIA to get the brake cables routed perfectly but finally did it. 6 months later, check them out. Rust in the housing! Anyone had similar experience?
Check out the pic:

In terms of weight-weenie-ness, what are preferred alternatives? I've used Nokons in the past; the housing tends to get creaky - and they are a PIA to install.

Any "traditional" casing (short of Nokon or the ceramic ones) is going to rust...the spiral-wound reinforcements or linear strands are made of plain (non-stainless) steel. It LOOKS ugly, but may only be a cosmetic concern unless you are also experiencing braking/shifting performance issues.

I am not too familiar with the Yokozuna kit...does it come with the sealing ferrules like some other brands?

Does your bike see regular encounters with water or high humidity environments?

Some of my cable sheathing has had discoloration/rust like this at the very ends when I had some clear types. I've not noticed it anywhere else along the cable. Being in So. Cal and my bikes not seeing rain probably helps. Since going to solid black or silver (Shimano) cables, I wouldn't know.

That is the reason i didnt go with the yoko. I have the gore ride on sealed/pro kits on my caad9 and couldnt be happier. The gore stuff is heavy though. Been running them on the mtb gears for a couple years and they are still going strong. I think gore is coming out with a light weight kit soon.

Performance seems ok

I have the same issue with them. Only seem to last a couple of months before rusting. The problem is that when they rust they become VERY stiff and braking performance suffers. No issues with the shifter cables though. I kept the Yokos for shifting and swapped out the brake cables for Clarks PreLubes. No rust issues and pretty good performance.

just use SRAM/Shimano/Campagnolo standard housings. They have done the job for years, why would you go exotic and more expensive ? Weight ? That's the most stupid reason I ever heard.

The main reason to use Yokos is not weight savings. Anybody who has held a Yokozuna cable set package will tell you that they feel really heavy. They actually weigh around the same as standard cable sets. The main reason is improved performance over the stock cables. I can tell you that performance, especially shifting, with SRAM shifters is GREATLY improved with the Yokozunas. Braking is very improved too but at the expense of the issues with rust mentioned here and also at the expense of issues due to the very stiff outers. Yes, standard Shimano cables do the job OK. Standard SRAM cables are OK but nowhere in the same league as Yokozunas. And the higher end SRAM offerings, the ones made by Gore, do offer really nice performance but the cable coating eventually gunks up and performance suffers. I can't vouch for Campagnolo as I've always used Shimano or SRAM.

However, I've been switching over to Clarks cables and they offer very good bang for the buck.

Braking is very improved too but at the expense of the issues with rust mentioned here and also at the expense of issues due to the very stiff outers.

Agree, and the downsides kind of negate any marginal improvment in actual brake performance. (The perceived improvement in "brake feel" is large, but that's another story). Keep in mind that parallel-strand compressionless housing is too weak to be used as brake housing. So Yokozuna has no choice but to wrap it with a metal spiral, increasing weight and stiffness. Using Yokos for shifting but not for braking seems like a reasonable compromise.